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Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 721 records · Page 40Linked to original sources
PubMed1989

The effects of intraventricular hemorrhage on functional communication skills in preterm toddlers.

A group of 24-month-old preterm toddlers (n = 27) were subdivided into three groups according to their early specific medical complications [i.e., respiratory distress syndrome (RDS), without intraventricular hemorrhage (IVH), IVH (Grades I and II), and IVH (Grades III and IV]) and were matched to a group of full-term toddlers (n = 10) on socioeconomic status and mental and receptive language age. We evaluated (1) the effects of IVH on functional use of language (e.g., speech acts), and (2) the relationship of mothers' verbal attempts to stimulate children's interest in topics and toys with the communication behaviors used by the children. The preterm groups used verbalizations and gestures less frequently to express a range of functions, but were comparable to the full-term children in their use of communicative acts that served to continue interactions. Although child behaviors did not differ in relation to specific medical complications, these differences were apparent in the mothers' behavior patterns and in the relationships between mother and child behavior. Mothers' verbal maintaining behavior was strongly associated with children's use of language for the full-term and two lower risk preterm groups, but not the higher risk IVH (Grades III and IV) group. The mothers of the IVH (Grades III and IV) group showed high responsiveness to lower level child behaviors, a pattern that was not apparent in the other preterm groups for lower risk children who showed comparable delays in their functional communication development.

Brain Damage, Chronic↗
PubMed1988

Chemical identification of cysteine as palmitoylation site in a transmembrane protein (Semliki Forest virus E1).

The palmitoylation site of the membrane glycoprotein E1 of Semliki Forest virus (SFV) has been identified by chemical analysis of an acylpeptide. 3H-Palmitoylated E1 isolated from SFV grown in baby hamster kidney cells was digested with chymotrypsin and the resulting peptides subjected to high performance liquid chromatography on a wide-pore column. The 3H-acylated peptide fraction peaked at above 60% 2-propanol in the eluent, indicating its hydrophobic character. Polyacrylamide gel electrophoresis analysis revealed a molecular weight of about Mr = 6000 for the radiolabeled peptide. Manual sequencing of this material by the 4-N,N'-dimethylaminoazobenzene-4'-isothiocyanate/phenylisothiocyanate procedure on solid phase revealed the amino-terminal sequence Ala-Ala-Ser-His-Ser-Asn-Val-Val-Phe-Pro. The same peptide also labels with [35S]cysteine. Comparison with the deduced amino acid sequence of E1 revealed that the palmitoylated peptide contains at least 43 amino acid residues, and thus includes the membrane spanning region down to the only cysteine residue five positions up from the carboxyl terminus of E1. Since [3H]palmitic acid was cleaved from E1 with thiol reagents, and since the peptide labels with [14C]iodoacetamide only after the release of fatty acids by hydroxylamine treatment, cysteine in position 433 represents the palmitoylation site in SFV E1.

Amino Acid Sequence↗
PubMed1988

Effects of sulfhydryl-containing compounds on nitroglycerin-induced coronary dilatation in isolated working rat hearts.

The effects of various compounds on the time course of the coronary dilating response to nitrovasodilators were studied in working rat hearts. Continuous administration of 100 microM glyceryl trinitrate (GTN) to the perfusate induced a rapid increase in coronary flow. The flow decreased to about 40% of the initial flow rise within 20 min and remained constant during the following 40 min. The flow increase induced by 100 microM SIN 1 (3-morpholino-sydnonimine), however, remained constant throughout the 60-min perfusion period. The decay of the GTN action was reduced in the presence of the thiol-containing agents L-homocysteine, L- and D-cysteine and to a lesser extent, reduced glutathione, while the initial response to GTN was only slightly enhanced. However, N-acetyl-L-cysteine caused a significant increase of the maximum response to GTN whereas the subsequent loss of GTN action was not greatly altered, suggesting that this agent exerts a potentiating action without altering tolerance. Dithiothreitol elicited a slight increase in the maximum effect of GTN, followed by a complete attenuation of the effect. These data suggest that SH group donors could exert different effects on the action of GTN while GTN tolerance is only influenced by L- and D-cysteine, L-homocysteine and reduced glutathione.

Amino Acids↗
PubMed1988

Acid phospholipase A activities in rat hepatocytes.

Cultured rat hepatocytes exhibit acid phospholipase A activity. On the basis of product formation from stereospecifically radiolabeled phosphatidylethanolamine substrates, phospholipases A1 and A2 have been identified with optimal activities at pH 4.5. According to subcellular fractionation studies, the acid phospholipases in hepatocytes appear to be located in the lysosomal compartment. Application of specific inhibitors of the biosynthesis, glycosylation, and translocation of lysosomal enzymes in hepatocyte cultures suggests a half-life of approx. 1 day for the acid lysosomal phospholipase A1. About the same value for the half-life was obtained for the lysosomal marker enzymes, acid phosphatase and beta-N-acetyl-D-hexosaminidase.

Animals↗
PubMed1988

Extraction of an infected tusk in an adult African elephant.

An 18-year-old African elephant was determined to have a nonrepairable crack in its left tusk. Treatment included extraction of the tusk, using rotational and extractional forces, and administration of antibiotics, followed by 1 year of flushing the opened tusk cavity with warm tap water. Two years after surgery, the elephant was healthy, and the tusk cavity was 80% filled with normal tissue.

Animals↗
PubMed1988

Immune response to hepatitis B revaccination.

Two hundred and twelve individuals who failed to respond or responded poorly to hepatitis B vaccination or whose anti-HBs levels had dropped below 10 IU/L at follow-up were revaccinated. Only 18% of initial nonresponders, but 96% of those who responded initially, developed anti-HBs above 10 IU/L after revaccination. In 85% of vaccinees, anti-HBs titres after a fourth immunization were significantly higher than after completion of the first full immunization course, and despite a steeper decline of antibody levels after revaccination, anti-HBs seemed to persist better than after the initial course of three inoculations. All individuals who responded initially and in whom anti-HBs had become undetectable developed antibodies. Response to booster doses was seen after three to five days, and a fifth inoculation given to 23 individuals induced even better responses.

Adult↗
PubMed1988

Persistence of specific antibodies after hepatitis B vaccination.

Antibody levels to hepatitis B surface antigen (anti-HBs) in healthy adults vaccinated with three doses of plasma-derived hepatitis B vaccine, containing 20, 10 or 5 micrograms of antigen, were followed for 4-6 years. After vaccination, 1034 of 1076 individuals had developed anti-HBs and 1016 had antibody concentrations above 10 IU/l. 681 of all initial responders could be tested after 1 year, 520 after 2, 380 after 3 and 213 after 4 years. 72 and 39 individuals, respectively, of the 185 earliest vaccinated volunteers were available for retesting after 5 and 6 years. Four years after the first vaccination, anti-HBs levels in 34% had dropped below 10 IU/l. The persistence of anti-HBs above this value depended on the peak antibody response after the third vaccination. Whereas all vaccinees tested with peak anti-HBs levels above 10,000 IU/l still had levels above 10 IU/l after 6 years, no-one with initial values between 10 and 100 IU/l maintained antibody concentrations above 10 IU/l for longer than 4 years. The rate of decrease in anti-HBs was independent of the peak anti-HBs value, the vaccine dose, and the age and sex of the vaccinees.

Adult↗
PubMed1988

New case of an EEC-like syndrome in twins.

A patient wrongly referred as a possible victim of thalidomide showed the three classical cardinal features of the EEC syndrome, plus severe mental retardation, an unusual finding in this condition. His twin brother was similarly affected, and died at four months of age due to complications caused by the malformations. Their normal parents were first cousins. The concordance of the manifestation in the twins and the parents' consanguinity suggest that they had the recessive form of the EEC syndrome.

Adult↗
PubMed1988

No evidence of vascular dopamine receptors in the rat portal vein.

Dopamine (5.3 X 10(-6) to 5.3 X 10(-5) M) decreased the force of spontaneous myogenic contractions of the rat portal vein in a concentration-dependent manner in the presence of the alpha-adrenoreceptor antagonist BE-2254. The DA1-selective agonist fenoldopam and the DA2-preferential agonist (-)-EOE were both inactive. Dopamine-induced relaxation was not inhibited by (+)-butaclamol (10(-8) M), but was reduced by a potent beta 2-selective adrenoreceptor antagonist ICI 118,551 (2 X 10(-8) M). Our results demonstrate that the rat portal vein is devoid of postsynaptic DA1 and DA2 dopamine receptors.

Adrenergic beta-Antagonists↗
PubMed1988

Binding of loop diuretics to their renal receptors: use as a screening model for potential diuretic activity.

Loop diuretics of the benzoic acid and aryloxyacetic acid families inhibit Na+K+Cl- cotransport. The ranking order of potencies measured in the thick ascending limb of Henle's loop and the ranking order of affinities for [3H]piretanide receptors on renal plasma membranes are the same. Potencies and affinities correlate well (correlation coefficient r = 0.959 for the medulla and r = 0.951 for the cortex). Therefore, measurement of [3H]piretanide binding is proposed to facilitate screening for loop diuretic action.

Animals↗
PubMed1988

Chicken homolog of the mos proto-oncogene.

We compared the sequence and properties of the chicken mos homolog with the previously characterized mouse and human c-mos genes. Sequence analysis revealed one major open reading frame of 1,047 base pairs encoding a protein of 349 amino acids. Both the nucleotide sequence and the deduced amino acid sequence showed 62% overall homology to mouse and human c-mos, but regions of higher conservation (approximately 70%) occurred in the putative ATP-binding and kinase domains. We detected mos transcripts by Northern (RNA) analyses in RNA prepared from chicken and quail ovaries and testes. Evidence for low levels of mos RNA expression in adult chicken heart, kidney, and spleen and in the entire embryo was obtained by S1 nuclease protection experiments. In contrast to the low transforming efficiency of human c-mos when linked to a mouse retroviral long terminal repeat element, chicken c-mos transformed NIH 3T3 cells as efficiently as mouse c-mos did. We also show that chicken primary embryo fibroblasts were morphologically altered when infected with an avian retroviral vector containing the chicken c-mos coding region.

Amino Acid Sequence↗
PubMed1988

[Metabolism and vascular effects of gammaglutamyl L-dopa on the isolated kidney of the rat].

The gammaglutamyl L-dopa (or gludopa), a dopamine (DA) prodrug, may be usefull in antihypertensive therapy as an orally active specific renal vasodilator. Indeed, gludopa is selectively metabolized in vivo by the kidney. This is the consequence of the sequential action of two renal enzymes, gamma-glutamyl transpeptidase (gamma-GT) and aromatic L-amino acid decarboxylase. The aim of this work was to elucidate, in vitro, the factors regulating its metabolism and to characterize its renal vascular effects. The rat kidney was isolated and perfused at constant flow in a closed circuit with a modified Krebs-Henseleit solution (BSA 6g/100 ml). Gludopa injection (10(-5) M) led to generation of DA (measured by gaz chromatography/mass spectrometry) in the venous effluent (134 +/- 39 ng/ml, n = 3) and in the urine (257 +/- 107 ng/mn/g). In non filtering kidneys, the level of DA in recirculating medium was depressed (47 +/- 5 ng/ml, n = 5; p less than 0.05). Glomerular filtration and access to the gamma-GT localized on the brush border membrane of proximal tubular cells are thus important for optimal metabolism of gludopa. Vascular effects of gludopa were studied on the isolated rat kidney after reestablishing vascular tone by continuous perfusion with prostaglandin F2 alpha (10(-8) M/mn) and after inhibition of alpha- and beta-adrenoceptors. Gludopa (3 X 10(-6) to 4 X 10(-5) M) induced dose-dependent renal vasodilation. At 4 X 10(-5) M, the renal response (30 +/- 3 p. 100 of the relaxation induced by 10(-4) M of papaverine) was similar to that elicited by DA at 20 fold lower concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗